Alliedsignal Inc.

Performance Fibers, Inc.

Jayendra H Bheda

Peter Bryan Rim

Charles J Nelson

James M Turner

A spun polyester fiber, a drawn polyester yarn, and methods for making them. Polyethylene terephthalate yarn is prepared by extruding a molten melt-spinnable polyethylene terephthalate having an intrinsic viscosity of at least about 0.8 through a shaped extrusion orifice having a plurality of openings to form a molten spun yarn; solidifying gradually said molten spun yarn by passing said molten spun yarn through a solidification zone which comprises (i) a retarded cooling zone and (ii) a cooling zone adjacent said retarded cooling zone where, in said cooling zone, said yarn is rapidly cooled and solidified in a gaseous atmosphere; withdrawing at sufficient speed said solidified yarn from said solidification zone to form a crystalline partially oriented yarn; and hot drawing said crystalline partially oriented yarn at a total draw ratio between about 1.5/1 and about 2.5/1 to produce a drawn yarn having an effective crosslink density (N) between about 10&#xd7;10and about 20&#xd7;10crosslinks per cubic centimeter. The yarns and fibers so prepared may be used to make treated tire cord having high tenacity in combination with improved dimensional stability.

Dimensionally stable polyester yarn for high tenacity treated cords

A spun polyester fiber, a drawn polyester yarn, and methods for making them. Polyethylene terephthalate yarn is prepared by extruding a molten melt-spinnable polyethylene terephthalate having an intrinsic viscosity of at least about 0.8 through a shaped extrusion orifice having a plurality of openings to form a molten spun yarn; solidifying gradually said molten spun yarn by passing said molten spun yarn through a solidification zone which comprises (i) a retarded cooling zone and (ii) a cooling zone adjacent said retarded cooling zone where, in said cooling zone, said yarn is rapidly cooled and solidified in a gaseous atmosphere; withdrawing at sufficient speed said solidified yarn from said solidification zone to form a crystalline partially oriented yarn; and hot drawing said crystalline partially oriented yarn at a total draw ratio between about 1.5/1 and about 2.5/1 to produce a drawn yarn having an effective crosslink density (N) between about 10&times;10 and about 20&times;10 crosslinks per cubic centimeter. The yarns and fibers so prepared may be used to make treated tire cord having high tenacity in combination with improved dimensional stability.

Polyethylene terephthalate yarn is prepared by spinning under high stress conditions in the transition region between oriented-amorphous and oriented-crystalline undrawn yarns by selection of process parameters to form an undrawn yarn that is a crystalline, partially oriented yarn with a crystallinity of 3 to 15 percent and a melting point elevation of 2 to 10&deg; C. The spun yarn is then hot drawn to a total draw ratio between 1.5/1 and 2.5/1 with the resulting properties: (A) a terminal modulus of at least 20 g/d, (B) a dimensional stability defined by E &plus;FS<13.5 percent, (C) a tenacity of at least 7 grams per denier, (D) a melting point elevation of 9 to 14&deg; C., and (E) anamorphous orientation function of less than 0.75. The resulting treated tire cord provides high tenacity in combination with improved dimensional stability.

Process of making dimensionally stable polyester yarn for high tenacity treated cords

Polyethylene terephthalate yarn is prepared by spinning under high stress conditions in the transition region between oriented-amorphous and oriented-crystalline undrawn yarns by selection of process parameters to form an undrawn yarn that is a crystalline, partially oriented yarn with a crystallinity of 3 to 15 percent and a melting point elevation of 2.degree. to 10.degree. C. The spun yarn is then hot drawn to a total draw ratio between 1.5/1 and 2.5/1 with the resulting properties: (A) a terminal modulus of at least 20 g/d, (B) a dimensional stability defined by E.sub.4.5 +FS&lt;13.5 percent, (C) a tenacity of at least 7 grams per denier, (D) a melting point elevation of 9.degree. to 14.degree. C., and (E) an amorphous orientation function of less than 0.75. The resulting treated tire cord provides high tenacity in combination with improved dimensional stability.

Process of making dimensionally stable polyester yarn for high tenacity

Dimensionally stable polyester yarn for high tenacity treaty cords

Polyethylene terephthalate yarn is prepared by spinning under very high-stress conditions wherein oriented-crystalline undrawn yarns are obtained. Selection of process parameters yields a partially oriented semicrystalline undrawn yarn with a crystallinity of 16 to 24 percent and a melting point elevation of 14.degree. to 22.degree. C. which is drawn to produce the resulting unique combination of properties: (A) a terminal modulus of at least 20 g/d, (B) a dimensional stability defined by E.sub.4.5 +FS&lt;11.5 percent, (C) a tenacity of at least 5 grams per denier, (D) a melting point elevation of 14.degree. to 22.degree. C., preferably 17.degree. to 20.degree. C., and (E) an amorphous orientation function of less than 0.75. The resulting treated tire cord unexpectedly provides high ultimate elongation and high toughness in combination with improved dimensional stability.

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Midlothian, VA, United States of America

Jayendra H Bheda